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How Different Can Dogs Get ? One Canus Tell

You all know what a sucker I am for a good dog yarn; so when I came across some recent research regarding the genetic and morphological variation in domestic dogs I was immediately drawn to a study that articulates the human determined direction of domestic dog evolution over the past 10K years, and specially the effect of human selection in confirming Darwin’s theory. Human intervention has allowed dogs to follow their own evolutionary paths, dumping Darwin’s soundbite, ‘survival of the fittest’, and proving him right in the bargain. The study was conducted by biologists Chris Klingenberg, of The University of Manchester and Abby Drake, of the College of the Holy Cross in the US.

Published in The American Naturalist on January 20, 2010, the study compared the skull shapes of domestic dogs with those of different species across the order Carnivora, to which dogs belong along with cats, bears, weasels, civets and even seals and walruses.

African Wild Dog

It found that the skull shapes of domestic dogs varied as much as those of the whole order. It also showed that the extremes of diversity were farther apart in domestic dogs than in the rest of the order. This means, for instance, that a Collie has a skull shape that is more different from that of a Pekingese than the skull shape of the cat is from that of a walrus.

Dr Drake explains: “We usually think of evolution as a slow and gradual process, but the incredible amount of diversity in domestic dogs has originated through selective breeding in just the last few hundred years, and particularly after the modern purebred dog breeds were established in the last 150 years.”

Asian Wild Dog

By contrast, the order Carnivora dates back at least 60 million years. The massive diversity in the shapes of the dogs’ skulls emphatically proves that selection has a powerful role to play in evolution and the level of diversity that separates species and even families can be generated within a single species, in this case in dogs.

Much of the diversity of domestic dog skulls is outside the range of variation in the Carnivora, and thus represents skull shapes that are entirely novel.

“Domestic dogs don’t live in the wild so they don’t have to run after things and kill them — their food comes out of a tin and the toughest thing they’ll ever have to chew is their owner’s slippers. So they can get away with a lot of variation that would affect functions such as breathing and chewing and would therefore lead to their extinction.

“Natural selection has been relaxed and replaced with artificial selection for various shapes that breeders favour.”

Dingo

Domestic dogs are a model species for studying longer term natural selection. Darwin studied them, as well as pigeons and other domesticated species.

Drake and Klingenberg compared the amazing amount of diversity in dogs to the entire order Carnivora. They measured the positions of 50 recognizable points on the skulls of dogs and their ‘cousins’ from the rest of the order Carnivora, and analyzed shape variation with newly developed methods.

The team divided the dog breeds into categories according to function, such as hunting, herding, guarding and companion dogs. They found the companion (or pet) dogs were more variable than all the other categories put together.

Pug

According to Drake, “Dogs are bred for their looks, not for doing a job so there is more scope for outlandish variations, which are then able to survive and reproduce.”

Dr Klingenberg concludes: “I think this example of head shape is characteristic of many others and is showing it so clearly, showing what happens when you consistently and over time apply selection.

“This study illustrates the power of Darwinian selection with so much variation produced in such a short period of time. The evidence is very strong.”

Story Source:

Adapted from materials provided by University of Manchester.

Journal Reference:

1. Chris Klingenberg and Abby Drake. Large-scale diversification of skull shape in domestic dogs: Disparity and modularity. The American Naturalist, January 20, 2010

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About Therese Trouserzoff

I think that in a just society, no mining magnate should be forced to go through life without a moral compass. OK for media magnates and cardinals to do so, apparently.

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27 thoughts on “How Different Can Dogs Get ? One Canus Tell”

While wild dogs are superior in their skill of survival with stalking and killing, nothing much has wilted in the survival instincts for pro-creating amongst our domestic dogs either.

We owned Bella. A lovely Border collie and as we got her as a pup, were rather lax in de-sexing her. Being at least a couple of kilometres away from nearest neighbours we never gave it much priority.

One morning we woke up with a racket on the veranda. There was a very good looking kelpie male chockers up Bella. He did not look at all bewildered or guilty. Not a hint of a ‘ sorry Mr Oosterman, but I just happen to pass by’.

Au contraire, he was really cool. The amazing part was that he had a 3 metre chain around his neck. I knew the dog and he was our neighbour’s best working dog, worth a fortune. Heaven knows how he could have broken loose, jumped fences and even knew our Bella was on heat.

A few weeks later a single pup, ‘Max’. A beautiful male kelpie with the working dog instincts of his father, soon started rounding alpacas. Alpacas can’t be rounded, in fact they are fox killers but no match for dogs working in packs of course.

Max was soon picked for real farmer’s work and was traded in for our ‘Milo’. Milo doesn’t chase alpacas, prefers rabbits and birds but beats any dog for sheer panache and personality.

They certainly do have an instinct for procreation. My 10 Kg west highland terrier, who is desexed, tried to mount a 40 kg bitch down at the beach. Her very well spoken mistress called him a ‘tart’, and shooed him away. I wanted to leave them to it, just to watch the mechanics of the whole thing!!!

I’ve been astounded at how quickly dog breeds have been bred. Some fairly unique breeds (euphemism for bloody silly) are only about a century old. Of course, they would all deteriorate into some mongrel hybrid, if allowed to do so.

I did see a programme on the ABC some years ago, about Russian scientists breeding some sort of Siberian Wolverine or fox, which was renown for tearing off human fingers, yet they were able to breed family friendly pets from them in about 30 to 40 generations. Perhaps we Australians should be doing the same with our native fauna?

They were silver foxes. Mad old Russian biologist, dead keen on Lysenko, hand rears foxes and constantly selects for the domestic dog like trait of tamability, whatever that is in its incipient form. You’re right, in thirty generations, (this was a mad obsessive life’s work!), the biologist had bred animals that looked much the same as the basal fox stock but behaved just like dogs.

“Why” is what beats the shit outta me. There was a lot of very, let’s call it, esoteric biology went on in the USSR under communism. They had a rather “Tom Cruise” attitude to psychology and psychiatry as well, except that it wasn’t a dose of L Ron that would cure you, but rather a swift course of re-education somewhere east of the Urals.

This is not a good day for me to read this article Warrigal, as interesting as it is. A large dog with an upset tummy went walkies on my footpath last night or early this morning. No prizes for guessing how I know this. As endearing and fun as dogs can be, many of their owners would be improved by a swift kick up their backsides.
I once went out with someone with a huge chip on his shoulders who told me that many dog owners use them to aggressively extend the owner’s territory. An ultimately tedious person, but sometimes I have cause to remember his words.

I once had a mate out near Brewarrina who had a heeler bitch suckle a litter of dingo pups. It’s not as simple as you might think. The enzymes and immunity factors in mammalian milk are species specific. That’s why it’s always best to breast feed if possible. It’s also why dogs don’t like cows milk as much as cats.

Some of the pups just didn’t thrive because they were unable to extract the nutrition from the domestic dog’s milk. Lactose intolerant humans are the same. In fact our ability to metabolise non human lactose is a very recent evolutionary adaptation specific to the earliest humans in Europe. Only about 10KYA. Ever wondered why the Chinese don’t enjoy cheese in the same numbers as Europeans? It’s not just a socio-cultural thing, though that is very important; the problem is many Asians have difficulty making any metabolic or nutritional use of non human lactose after they’re weaned.

I cut a snippet out of our local rag a couple of weeks ago. It has been sitting by my laptop waiting for me to think up some amusing crack, which I haven’t been able to do!

It is headed… Natural Killers

Murris called dingoes warrigals and lived closely with them. When Europeans arrived, they crossed their dogs with dingoes hoping to pick up some of the traits of the local animal.
They ended up with tough breeds such as kelpie and blue heeler. Graziers now fear dingoes for their hunting abilities.
A dingo can kill up to 50 sheep in a night, though eating very little.

I’d check those figures J. Say there’s 10 hours of dark. That means your dingo has to kill a sheep every twelve minutes until sun up. Does that sound plausible to you? Most sheep kills in Queensland are not committed by Dingos but rather by packs of feral domestic dogs or cross bred Dingo/Dogs.

Dingos don’t like humans and tend to stay away. Of course feral dogs have no such fear. This is not to say that Dingos don’t kill stock but you only have to witness the panic a stock killing carnivore has on farmers. They’d kill every non human meat eater in sight if it were up to them, and maintaining the rage against these “wild” dogs is all part of the ongoing failure to acknowledge the reality of farming and grazing in Australia.

Just as the greatest threat to native lizards and birdlife is the domestic cat, so dogs are far more prevalent killers than dingos when it comes to livestock.

Domestic dogs have certainly killed or maimed many alpacas. Especially if the hobby farms are situated close to subdivisions, where there are lots of dogs.
The owners think that their pet dogs are ‘nice’ and don’t believe their darlings can become killers. This usually happens when there are two or more dogs together roaming about.

We have been lucky because we are surrounded by real farms and real farmers, who keep their dogs under lock and key, (not quite), and they also shoot any roaming dog they see.

We once sold two of our best alpacas to Queensland; after a week or so , I got this stressed new owner of Nadia and her beautiful son Tuan, calling me early Saturday morning to let me know that her neighbour’s nice dogs had killed both alpacas.

J, Spaniels are one of the breeds that only exist because of the plasticity of dog morphology and the fact that a pretty spaniel is an adorable thing. I once shared a house with a young woman who kept a King Charles Cavalier. Silliest dog I’ve ever met but loving beyond measure. I remember it snored fit to wake the devil.

I read somewhere that too much interbreeding can affect the shape of their skulls. This can lead to all sorts of problems. And of course the poor little bastards can’t tell you!

In the UK we had two which begat/ begot? two litters. So we became accidental breeders. One of them won prizes at the country shows. We lived on The IOW then; and at one time had Farley, the labrador, Samson the mad Irish setter, the cavaliers with their pups…and about 4 cats….Oh plus the goats and the ponies.

Samson used to run away and the farmers threatened to shoot him, as he worried all their cattle and sheep—so we found a home for him.

Spaniels are “chasing” dogs and it’s very difficult if not impossible to train that out of them. I’d never walk a Spaniel on a busy city street without a lead. They just can’t be trusted not to shoot off after something and get skittled.

My Dad had a Red Setter before he met our Mum. He was working on the gold fields in WA and used to go rabbiting with the dog. It was too silly to keep out of its own way and would often get tangle footed in the scrub. Useless as a hunting dog but Dad loved it apparently. It fell down an abandoned shaft and broke its neck, poor bugger.

As kids in Finland we were a teeny bit worried about running into a Siberian wolf when playing in a forrest. There were always stories about them being sighted in the northern part of the country, especially when the winters were extremely cold.

The Asian Wild Dog and the yellow Pariah Dogs of India are the precursors to the Dingo which only arrived in Australia after about 4KYA. It may look cuddly but wild dogs anywhere are intelligent animals organised in hierarchical packs, not unlike us. They are efficient co-operative predators with an enormously powerful bite used most often, like many other members of the Carnivora, to put a choke hold on the throat, thereby asphyxiating their prey.

Pound for pound the African Wild Dog has the strongest bite of any species within the order Carnivora and to watch them hunt and attack is like watching those green grainy night vision images of SAS troops; the line up and spread, the deception and decoying, the attack, the kill, and then the all important slipping back into the woods for a good nosh. It’s just a trip to the supermarket for them.

All wild dogs can be at least partially familiarised, habituated to humans, at least to the extent that you can get them to approach and accept food. but none can be said to be truly human friendly. They are wild animals separated from their domestic cousins by 10K years of human association.

It’s fascinating to note that other research has shown that domestic dogs will perform poorly in terms of efficiency of process if such poor performance increases the regard the Alpha Pack Member has for the individual at the time of testing. They will none the less revert to a more efficient process when performing the same test with out human observers.

Mans best friend. They’re happy to be our fools, but they’ve got our number. Talk about “sit” and “rollover”.

Which brings me back to a movie some years ago called ‘Mondo Cane’.
It was supposed to be critical of the human species making their habitat more and more ‘a dog’s world’. If only it was.
Milo is still the best dog we ever had. He has trained us well.

I’ve always suspected this but it’s fascinating to see the research behind it. Next time I do an IQ test and I see the question “Collie is to Pekingese” I will be sorely tempted to write “as cat is to walrus.”

A canine Milo Minderbinder. Just be careful if he offers to corner the Egyptian cotton market at a time of falling chocolate futures.

I always wondered about that company that set up with the name “Mondo Cane” and sold bamboo and woven grass furniture from the Philippines. Had they ever seen the movie or was it just a case of the catchiness of the phrase. “I’ll have the lounge over there and some Trobriand Island land diving and a kilo of warm monkey brains to go.”

Nev, it’s astonishing the morphological variation in dog skulls. The reason I used the Pug as my final illustration was because the amount of remodeling that has had to go on within that tiny little skull is incredible. It’s like a piece of miniaturised high tech. All the parts are in there but they all look different and many are in completely novel locations.

Yet put a Pug and a Shepherd in the same room and it’s not always going to be the case that they’ll organise themselves along size lines. It seems that dogs recognise an essential “dogness” in other dogs irrespective of size, shape or colouring. Though they will more often organise along size lines, physical strength being an important component of a successful hunt, intelligence is highly prized and given the highly social nature of the pack and the highly developed hunting communication skills displayed by dog packs, it can often be the case that a smaller dog will be the leader in the hunt yet cower behind the larger dogs when involved in territorial disputes with other packs. Horses for courses.